U.S. Publication No. 20070270924 and International Publication No. WO12007/112578 describe a single-coil RF (radio frequency) electrode, along with an associated method of operation, for use in an RF applicator, RFA (radio frequency ablation) apparatus or RFA system for heating tumors, including large tumors with a single heating session. The RF electrode generally has a helical geometry, although many variations exist, and is provided with an excitation current having a frequency that is sufficient for magnetic induction and coupling of various electric and magnetic fields to produce an electric field within the volume surrounded by the coil for directly applying heat to the tissue therein. U.S. Publication No. 20070270924 and International Publication No. WO/2007/112578 are each hereby incorporated herein by reference in their entirety.